Bigger lesson is: do not utilize cloud solutions. Your organization's competency floor is set to the least competent employee of the cloud provider.
What I will say is it's important for the customer to HAVE THEIR OWN BACKUPS. Don't rely on the vendor - that's the lesson here. If you have all your stuff in AWS back that data up someplace that's not AWS, etc.
Some examples: https://www.ownbackup.com/ https://www.backupify.com/ https://www.cloudally.com/
Edit: to clarify I would say if the data is important to you, then “the ability to back up the data” should be a requirement when selecting saas. See my other comment in this thread on ms planner.
Even for Email or storage or any other open system, UX changes and feature differences can take a lot of time to train properly, you don't migrate from one vendor to another vendor just like that.